Siege weapons and defense weapons in ancient China

This is a picture of the Chuang Zi Nu (床子弩) or the Mechanical Siege Crossbow. It was a siege crossbow used during Tang and Sung dynasties. This siege crossbow was about 8 metres long, and it was comprised of three bows. It required a whole team of men to operate this siege crossbow. It also required a winch to turn the axle and to load the string on the trigger. This siege crossbow was extremely powerful, and it had a maximum range about 800 meters or more.